paul-g

i ahve an 07 550i and now live in the south. i was wondering cause it is alot hotter in SC than CT during the summer i was wonder what weight would be best to use? can't seem to fin any castrol or mobile 1 (euro formula of course) that is 5-30 only 0-40 which owners manual doesn't show and dealer/stealer wants $11.82 a quart.

I need to do oil change before friday any help would be awesome!

twh

Walmart sells 5 gallon jugs of Mobil 1 0W-40 cheaper than any place I have seen.

paul-g

they don't have the euro blend though which bmw lists as "ok" to use and like i stated my 550 says 5-30 and doesn't list the "0" of any weight

BimmerFan52

I wouldn't worry about the oil viscosity if you are going to use a synthetic. The ambient temperature really doesn't have a dramatic effect on engine oil operating temperature. The oil gets hot because it is helping cool the engine block which has explosions going on inside it. The oil still gets hot even if it is -30F outside. The big difference with synthetic is how well the oil flows quickly at very low temperatures to begin lubricating the engine during startup.

The number next to the W is the winter viscosity, which is an industry standard that measures the amount of force required to crank a reference engine at a certain ambient temperature. A lower W number means that the oil remains less viscous and the engine will crank easier. The W number has NOTHING to do with the oil when measured at operating temperature, which is the second number, and the W number also has nothing to do with the old oil system of grades or weights.

The second number is the viscosity of the oil when measured at 100C and is a measure of how "thin" (not a term used in the world of engineered fluids, but a good layman's term) the oil gets when hot. If the oil gets too "thin" (kinematic viscosity gets too low) it can stop protecting the engine because it no longer keeps metal parts separated by a film of oil (oil cannot support a hydrodynamic film).

Mobil1 0W-40 is the Euro-Blend, and as twh stated, is available at Wally-World for $5/qt (if it isn't available at your Walmart you can order it to have it shipped for free to the store at the same price). It doesn't get any cheaper for a fine oil. I use it in all of my cars here in Arizona as the second number, 40 means it stands up well to high heat. It is the best of both worlds, as if I go in the winter up to the Mountains in Flagstaff and it is -20F, the 0W winter rating is as good as it gets for cold engine starting.

Also remember that the second number represents a lab measured kinematic viscosity at 100C that falls within a certain range. The oil can be at the low or high end of that range. The BMW labeled oil is a 5W-30, meaning it is a 30 grade oil at 100C. But it is at the high end of the 30 grade range. The Mobil1 0W-40 is a 40 grade oil at 100C, but is at the lower end of the 40 grade range. The bottom line is that in use, the BMW 5W-30 oil and Mobil1 0W-40 will be extremely close in operating temperature performance. Don't get hung up on numbers.

Mobil1 is my personal choice. But there are many good synthetic oils on the market and ALL of them will do a great job protecting your engine. Just remember to change your oil before the additives are used up. They are the real magic of the oil.

tonyb635

I've always ran 5 w 30 mobile 1. Walmart, advance,AZ. I also live in SC.

paul-g

Okay wanted to be sure. Not sure why i couldn't fine the 5w30 like normal....now onto why sirus all of a sudden doesn't work ( see other post) ugggg

Thanks for the help

paul-g

Tony where abouts in SC are you? Florence for me

tonyb635

Greenville, been here about 20 yrs now.

twh

Mobil 1 0W-40 is BMW LL-01 approved. It lists that on the bottle.

pcy

^ +1